Self-propelled anti-aircraft weapon
An anti-aircraft vehicle, also known as a self-propelled anti-aircraft gun (SPAAG) or self-propelled air defense system (SPAD), is a mobile vehicle with a dedicated anti-aircraft capability.
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Specific weapon systems used include machine guns, autocannons, larger guns, or missiles, and some mount both guns and longer-ranged missiles (e.g. the Pantsir-S1). Platforms used include both trucks and heavier combat vehicles such as armored personnel carriers and tanks, which add protection from aircraft, artillery, and small arms fire for front line deployment.
Anti-aircraft guns are usually mounted in a quickly-traversing turret with a high rate of elevation, for tracking fast-moving aircraft. They are often in dual or quadruple mounts, allowing a high rate of fire. In addition, most anti-aircraft guns can be used in a direct-fire role against surface targets to great effect. Today, missiles (generally mounted on similar turrets) have largely supplanted anti-aircraft guns, but they may return as an cheap way to counter unmanned aerial systems (drones).